It is well known in the art that a woman's menstrual cycle occurs approximately once a month. For obvious reasons, women monitor the number of days that have passed since their last menstrual cycle or so-called "menses." Indeed, most women, if not all, mark off a fixed number of days from their last menstrual cycle on a calendar to determine when their next period is due. While this method is simple and inexpensive, it also has a number of drawbacks. First, a woman must remember the date of her last menstrual cycle. Second, if a woman incorrectly counts the number of days from her last cycle, she will also make a mistake when her next menstrual cycle or period is due. Third, women who monitor their ovulation, such as for birth control or fertility, can likewise incorrectly count the number of days, and thereby erroneously time the period during which to abstain from or engage in sexual intercourse. Similarly, using this latter method, women can also make a mistake about when to expect pre-menstrual syndrome (PMS), which occurs several days before and after a woman's period.
In the prior art, various attempts have been made for monitoring a woman's menstrual cycle. Most notably, U.S. Pat. No. 4,527,906 to Jezbera discloses a digital watch module that displays the number of days that have passed since the start of a woman's last menstrual cycle. One primary drawback of the foregoing prior art, however, is its inability, among other things, to display information relating to a woman's menstrual cycle in a manner that is readily useful to a woman. For example, from the displayed information of Jezbera, a woman must still use, for example, a calendar to determine the dates of her last and next menstrual cycles, as well as the dates of her ovulation and pre-menstrual syndrome.
Another drawback in the prior art is its inability to automatically monitor for variations in a woman's cycle. This is especially important inasmuch as women's cycles vary by an average of about seven to thirteen days for peak reproductive years and by even a greater amount for girls in their teens and women approaching menopause.